TNF and inflammatory bowel disease: Likewise, Bosè et al. evidenced a dual effect in patients with PsO and IBD, in which TNF blockade was capable of inducing an augmented responsiveness of peripheral T cells to TCR-stimulation and an increased secretion of cytokines ex vivo, whereas in biopsies from target tissues TNF blockade led to a dramatic reduction of Th17 and Th1 responses13.